🚀 go-pugleaf

<fnord>

I have a question about the functioning of turbo and super chargers.

First, be warned!  The early part of this article contains factual
errors, do not skim it and then flame me saying "You're wrong!", I know
I am, that is why I want the answers.

Both turbos and supers compress air and put it inside of the engine.
The reason why you do this is that you need more oxygen to burn in
addition to more fuel.  A super charger is mechanically coupled to the
engine.  If the engine is turning a x rpm then the super charger is
turning at sc(x) where sc() is linear.  The same is not true of
turbos.  The turbo is fluidly coupled (air is a fluid) to the engine.

I had thought that `if the engine is turning at x rpm then the turbo is
turning at tc(x) where tc() is a linear function ONLY AT TIME t sub zero
after the engine reaches x rpm.'

This is the source of turbo lag.  The turbo must `catch up' to the
engine.

Well my boss let me drive his car (Saab 900 Turbo w/16 valves and APC,
btw, this is a nice car (too bad it's been broken into twice in the past
year)) the other day and it became obvious that the above is not true.

Take the case where you are charging down the road at 4,000 rpm and you
let up on the throttle without depressing the clutch.  Under the above
theory the turbo would continue spinning at tc(4000) since the engine is
still at 4,000 rpm.  However the boost guage indicated an IMMEDIATE drop
in boost.

QUESTION:

why is this so?

Any takers?


(super charger trivia --  back in the 50's a lot of MG owners put
superchargers on their cars.  Name the city that made (most) of these
and name at least one other metal sporting good part that this city
made.  hint:  it's near my hometown :-)

					pZ
-- 
-- My wife ran off with my best friend, and I miss him.

   Paul Czarnecki
   Uniworks, Inc.		decvax!{cca,wanginst!infinet}!emacs!pz
   20 William Street		emacs!pz@cca-unix.ARPA
   Wellesley, MA 02181		(617) 235-2600